Chlamydia trachomatis is an intracellular bacterial pathogen that colonizes and infects oculogenital surfaces. Ocular infections of Chlamydia trachomatis cause trachoma, a chronic follicular conjunctivitis that results in scarring and blindness. The World Health Organization (WHO) estimates that 300-500 million people worldwide are afflicted by trachoma (Resnikoff et al., Bull. WHO 82:844-851, 2004), making it the most prevalent form of infectious preventable blindness (Whitcher et al. Bull. WHO 79:214-221, 2001). Urogenital infections are the leading cause of bacterial sexually transmitted diseases (Division of STD Prevention, Sexually Transmitted Disease Surveillance 1997, Centers Dis. Cont. Prev., Atlanta, 1998) in both developing and industrialized nations (WHO, Global Prevalence and Incidence of Selected Curable Sexually Transmitted Infections: Overview and Estimates, WHO, Geneva, 2001). Moreover, sexually transmitted diseases are risk factors for the transmission of HIV (Plummer et al., J. Infect. Dis. 163:233-239, 1991), infertility (Westrom et al., Sex. Trans. Dis. 19:185-192, 1991), and human papilloma virus-induced cervical neoplasia (Anttila et al., J. Am. Med. Assoc. 285:47-51, 2001).
For all the above reasons, control of C. trachomatis infections is an important public health goal.